Metal sheet bending device with rotation inhibiting function

Abstract

A metal sheet bending apparatus includes first and second lower bar molds each having a section of a semicircular shape. The first and second lower bar molds are rotatably provided in first and second concave portions of a support, respectively. First and second adjust screws are attached to first and second pull-up rods, respectively at an opposite side of the portions with respect to first and second stoppers. An upper mold is adapted to bend a metal sheet placed on metal contact surfaces of the first and second lower bar molds by pressing the metal sheet above a groove of the support while the first and second lower bar molds rotate against spring force given by first and second push springs such that the metal contact surfaces form a V-shape.

What is claimed is:  
     
       1. A metal sheet bending apparatus comprising: 
       a support having first and second concave portions each having a section of a semicircular shape, a groove being formed between the first and second concave portions;  
       first and second lower bar molds each having a section of a semicircular shape, the first and second lower bar molds having metal contact surfaces, respectively and being rotatably provided in the first and second concave portions, respectively such that the semicircular shape of each of the first and second lower bar molds fits in the semicircular shape of each of the first and second concave portions;  
       first and second pull-up rods having end portions, respectively, the end portions being rotatably connected to the first and second lower bar molds, respectively;  
       first and second stoppers provided to the support, the first and second pull-up rods passing through the first and second stoppers, respectively;  
       first and second adjust screws attached to the first and second pull-up rods, respectively at an opposite side of the end portions with respect to the first and second stoppers;  
       first push spring provided between the first stopper and the first adjust screw;  
       second push spring provided between the second stopper and the second adjust screw, spring force given by the first and second push springs being adjusted by the first and second adjust screws; and  
       an upper mold adapted to bend a metal sheet placed on the metal contact surfaces of the first and second lower bar molds by pressing the metal sheet above the groove while the first and second lower bar molds rotate against spring force given by the first and second push springs such that the metal contact surfaces form a V-shape.  
     
     
       2. The metal sheet bending apparatus according to  claim 1 , wherein the first and second lower bar molds have recessed portions extending along a longitudinal direction of the first and second lower bar molds, the recessed portions forming a V-shaped cross section. 
     
     
       3. The metal sheet bending apparatus according to  claim 1 , wherein a cushion material surface, a sliding surface, or a sintered carbide surface are formed on the metal contact surfaces. 
     
     
       4. The metal sheet bending apparatus according to  claim 1 , wherein the cushion material surface comprises urethane, vinyl, or cloth. 
     
     
       5. The metal sheet bending apparatus according to  claim 1 , wherein the sliding surface includes hard chromium plating, non-electrolysis nickel plating, a hardening surface, or a hard heat treatment surface. 
     
     
       6. The metal sheet bending apparatus according to  claim 1 , wherein the sintered carbide surface is formed through electric discharge by applying voltage between the metal contact surfaces and an electrode comprising tungsten carbide cobalt or titanium carbide. 
     
     
       7. A metal sheet bending apparatus comprising: 
       a support having first and second concave portions each having a section of a semicircular shape, a groove being formed between the first and second concave portions;  
       first and second lower bar molds each having a semicircular shaped section along a surface perpendicular to a longitudinal direction of the first and second lower bar molds, the first and second lower bar molds having metal contact surfaces, respectively and being rotatably provided in the first and second concave portions, respectively such that the semicircular shaped section of each of the first and second lower bar molds fits in the semicircular shape of each of the first and second concave portions, the first and second lower bar molds having recessed portions on the metal contact surfaces along the longitudinal direction at a contact portion between the first and second lower bar molds;  
       first and second pull-up rods having end portions, respectively, the end portions being rotatably connected to the first and second lower bar molds, respectively;  
       first and second stoppers provided to the support, the first and second pull-up rods passing through the first and second stoppers, respectively;  
       first and second fixture attached to the first and second pull-up rods, respectively at an opposite side of the end portions with respect to the first and second stoppers;  
       first push spring provided between the first stopper and the first fixture;  
       second push spring provided between the second stopper and the second fixture; and  
       an upper mold having a rounded tip and adapted to bend a metal sheet placed on the metal contact surfaces of the first and second lower bar molds by pressing the rounded tip against the metal sheet above the groove and further to bend the metal sheet to be a U-shape while the first and second lower bar molds rotate against spring force given by the first and second push springs such that the metal contact surfaces form a substantially V-shape.  
     
     
       8. The metal sheet bending apparatus according to  claim 7 , wherein a cushion material surface, a sliding surface, or a sintered carbide surface are formed on the metal contact surfaces. 
     
     
       9. The metal sheet bending apparatus according to  claim 8 , wherein the cushion material surface comprises urethane, vinyl, or cloth. 
     
     
       10. The metal sheet bending apparatus according to  claim 8 , wherein the sliding surface includes hard chromium plating, non-electrolysis nickel plating, a hardening surface, or a hard heat treatment surface. 
     
     
       11. The metal sheet bending apparatus according to  claim 8 , wherein the sintered carbide surface is formed through electric discharge by applying voltage between the metal contact surfaces and an electrode comprising tungsten carbide cobalt or titanium carbide. 
     
     
       12. A metal sheet bending apparatus comprising: 
       a support having first and second concave portions each having a section of a semicircular shape, a groove being formed between the first and second concave portions;  
       first and second lower bar molds each having a semicircular shaped section along a surface perpendicular to a longitudinal direction of the first and second lower bar molds, the first and second lower bar molds having metal contact surfaces, respectively and being rotatably provided in the first and second concave portions, respectively such that the semicircular shaped section of each of the first and second lower bar molds fits in the semicircular shape of each of the first and second concave portions, the first and second lower bar molds having recessed portions on the metal contact surfaces along the longitudinal direction at a contact portion between the first and second lower bar molds;  
       first and second pull-up rods having end portions, respectively, the end portions being rotatably connected to the first and second lower bar molds, respectively;  
       first and second stoppers provided to the support, the first and second pull-up rods passing through the first and second stoppers, respectively;  
       first and second adjust screws attached to the first and second pull-up rods, respectively at an opposite side of the end portions with respect to the first and second stoppers;  
       first push spring provided between the first stopper and the first adjust screw;  
       second push spring provided between the second stopper and the second adjust screw, spring force given by the first and second push springs being adjusted by the first and second adjust screws; and  
       an upper mold having a rounded tip and adapted to bend a metal sheet placed on the metal contact surfaces of the first and second lower bar molds by pressing the rounded tip against the metal sheet above the groove and further to bend the metal sheet to be a U-shape while the first and second lower bar molds rotate against spring force given by the first and second push springs such that the metal contact surfaces form a substantially V-shape.